Giant piranhas had deadliest mega-bite

Posted December 21, 2012 - 06:35
by
Flora Malein

Scientists believe the extinct giant Miocene piranha had one of the strongest bites ever recorded in any fish or land animal.

Piranhas are well known for their sharp teeth and strong appetites for fresh meat. They are a predatory fish, hunting in large schools and are capable of killing any unwary humans who enter their waters. A study of today’s living piranhas has revealed that the giant piranhas that swam the rivers of the Miocene between 5 and 20 million years ago would have had the strongest bite of any known mega-predator.

In a paper published in Nature, scientists analysed the fossil remains of the giant piranha species, Megapiranha paranensis, and compared its bite to that of its largest living relative, the black piranha, Serrasalmus rhombeus. M. paranensis, may have reached lengths of three feet which is more than three times the size S. rhombeus, but is still relatively small compared to other ‘megafauna’ species that would have existed at the time.

By reconstructing the bite force of M. paranensis, the scientists found that despite its relatively small size, this ancient predator was capable of generating forces between 1,240 and 4,749 N, a maximum force equivalent to roughly 1,124 pounds or 500 kg. This mega-force is much greater than anything used by other extinct mega-predators, such as the huge whale-eating shark, Carcharodon megalodon, and the Devonian placoderm, Dunkleosteus terrelli.

The large bite of both M. paranensis and S. rhombeus is created by a giant muscle complex located above and behind its jaw. Analysis of the fossil piranha’s teeth suggest it was capable of both slicing through soft flesh and crushing hard prey. However, the authors are still unsure on what exactly M. paranensis would have fed on.

"The diet of this giant piranha species still remains a mystery," they write.

"The Miocene epoch is renowned for its gigantism in Neotropical aquatic flora and fauna. Thus, it is reasonable to assume the food resources available to Megapiranha would likely have required jaw forces and dental weaponry capable of capturing and processing very large prey."

Their findings also confirm that today’s living piranhas are among the most powerful predators when it comes to the force of their jaw.

"While anecdotes of piranha-infested waters skeletonizing hapless victims are generally hyperbole, the effectiveness of their bite is not," say the authors.

"Even at their small body sizes, diet studies indicate that piranhas will attack and bite chunks out of prey many times larger than themselves."